1. Field of the Invention
The present invention relates to an inkjet recording apparatus for recording an image by ejecting ink and to a remaining amount of ink detecting method in the image recording apparatus.
2. Description of the Related Art
There is conventionally known a so-called serial type inkjet recording apparatus for recording an image by repeating a recording operation for recording an image in correspondence to one scan by canning an inkjet head acting as a recording means in a main scanning direction and a transport operation for transporting a recording medium in a sub-scanning direction different from the main scanning direction. Further, there are also known, as the serial type inkjet recording apparatus, an inkjet recording apparatus that has a carriage on which a print cartridge provided with an inkjet head integrated with an ink tank (hereinafter, referred to also as a xe2x80x9cinkjet cartridgexe2x80x9d) is mounted and records an image by scanning the carriage in a main scanning direction relatively to a recording medium; and an inkjet recording apparatus that has an inkjet head arranged separately from an ink tank, mounts them on a carriage, and records an image by scanning the carriage.
The inkjet recording apparatus is widely utilized in a printer that prints an image based on a command output from an application program and the like installed on a computer acting as a host apparatus; in a copy machine that is integrated with a scanner for reading an image on a document and prints a copy of the image; in a facsimile for receiving, transmitting and outputting an image on a document through a signal line such as a phone line; and the like because it is easy to reduce the noise, running cost, and size of the inkjet recording apparatus.
The recording apparatus that records an image by the inkjet system employs various technologies to detect a remaining amount of ink in an ink tank mounted on the apparatus. Known as the technologies for detecting the remaining amount of ink are a method of optically detecting a liquid surface level of ink in an ink tank; a method of placing a buoyant float in an ink tank and detecting the position of the float using various sensors; a method of optically detecting an ejected ink droplet and determining whether or not ink is present based on whether or not ink is ejected; and the like.
Japanese Patent Laid-Open No. 2-102061 discloses a technology for detecting the absence of ink by a reflecting plate and a reflection type sensor that are disposed in an ink tank. Further, Japanese Patent Laid-Open No. 56-144184 discloses a technology for notifying the absence of ink after a predetermined period of time passes from the time it is detected as a countermeasure for preventing that the fluctuation of liquid surface of ink decreases an accuracy with which a remaining amount of ink is detected.
Furthermore, proposed as the technologies for detecting an amount of ink remaining in an ink tank are Japanese Patent Laid-Open No. 60-24954 which discloses a technology for determining that no ink is supplied due to the reduction in a remaining amount of ink by detecting the negative pressure in an ink supply pipe; Japanese Patent Laid-Open No. 60-127162 which discloses a technology for detecting an electric resistance between two electrodes disposed at positions where they are in contact with ink; Japanese Patent Laid-Open No. 07-164626 which discloses a technology for irradiating light to an ink tank, detecting light reflected thereon, and detecting the reduced state of an amount of ink in the ink tank; and so on.
As described above, the methods of detecting a remaining amount of ink in an ink tank and the methods of determining whether or not ink is present are conventionally well known. However, the method of detecting a liquid surface level in an ink tank may not obtain an accurate result of detection because of the fluctuation of a liquid surface, which is caused by the movement of a carriage, and surface tension. The method also requires complicated control to increases an accuracy. Further, in the method of optically detecting an ink droplet, a phenomenon, in which mist of tiny ink droplets is formed as ink droplets are ejected (hereinafter, simply referred to as xe2x80x9cmistxe2x80x9d), may occur as well as an ink droplet may be detected by mistake by the influence of dusts and the like. Thus, a result of detection may become unstable.
In particular, the conventional arrangements described above require to add a mechanism for detecting a remaining amount of ink, by which a problem is arisen in that the size of the inkjet recording apparatus and the cost thereof increase.
An object of the present invention, which was made in view of the above conventional examples, is to provide an inkjet recording apparatus capable of detecting a remaining amount of ink accurately without adding a new component to a conventional recording apparatus and without increasing a cost while maintaining the apparatus in a small size and to provide a remaining amount of ink detecting method.
To achieve the above object, the present invention is characterized in an inkjet recording apparatus that includes a carriage on which an ink accommodation unit for accommodating ink and a head unit for ejecting ink can be mounted; a main scanning unit for scanning the carriage along a main scanning direction by driving a motor; a position detection unit for detecting a position of the carriage that is scanned by the main scanning unit; a control unit for driving the motor to cause the main scanning unit to scan the carriage from a predetermined position in the scanning region of the carriage along the main scanning direction and then stopping the drive of the motor; and a determination unit for determining an amount of ink remaining in the ink accommodation unit based on a result of moving state of the carriage detected by the position detection nit after the drive of the motor is stopped by the control unit.
Further, to achieve the above object, the present invention is characterized in a method of detecting a remaining amount of ink in an inkjet recording apparatus including a carriage on which an ink accommodation unit for accommodating ink and a head unit for ejecting ink can be mounted and main scanning means for scanning the carriage along a main scanning direction by driving a motor, the method including the steps of scanning the carriage by the main scanning means from a predetermined position of the scanning region of the carriage along the main scanning direction by driving the motor; stopping the drive of the motor at predetermined timing while the carriage is being scanned at the scanning step; and determining the amount of ink remaining in the ink accommodation unit based on the moving state of the carriage after the stopping step.
According to the present invention, the amount of ink remaining in the ink accommodation unit can be determined based on the moving state of the carriage moved by inertia when the motor is stopped after the carriage, on which the ink accommodation unit for accommodating ink and the head unit are mounted, is scanned. As a result, the remaining amount of ink can be detected by a simple arrangement without the need of a special mechanism and part for detecting the remaining amount of ink.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.